Various forms of safety electrical plugs heretofore have been provided for use in conjunction with extension cords to be plugged into a wall socket or the like. Such safety plugs include various types of sleeves which are extendible and retractable relative to the outwardly projecting terminals of the plugs and which at least substantially enclose the outer ends of the terminals when the plugs are not plugged into receptacles and which are automatically retractable to expose the plug terminals as the plug is engaged with a receptacle. However, many of these safety plugs are complex in structure and include protective sleeve portions which, when fully extended, do not fully enclose the free ends of the outwardly projecting terminals of the associated plugs. In addition, few, if any, efforts have been made to provide an adapter for a conventional male plug into which the terminals of the male plug may be telescoped and electrically connected with terminals of the adapter with which a retractable cover sleeve is operatively associated.
Accordingly, a need exists for an improved form of electrical plug having a retractable terminal enclosing sleeve operatively associated therewith and which may be of simple construction and readily incorporated in the manufacture of extension cords and the like having male plugs on specified ends thereof. In addition, a more immediate need exists for an adapter type plug which may be utilized to transform conventional male plugs into plugs equipped with terminal shielding safety sleeves.
Examples of safety plugs, including some of the general structural and operational features of the instant invention, are disclosed in U.S. Pat. Nos. 2,082,986, 2,396,901, 3,513,435, 3,575,684 3,629,790 and 3,754,205.